Q. My asparagus attempt resulted in five out of 10 crowns
dying. I did as you suggested and dug
down as deep as my tiller would dig about 13″. For better drainage I drilled holes another
12″ deeper and filled them with gravel. I ordered Jersey Knight asparagus
and planted as per their instructions as well.
Asparagus planting done in late fall or very early spring with amended soil with compost or aged manure. Drip irrigation can be used but watering should follow a similar pattern to watering fruit trees.
A. The usual reason for asparagus dying or growing poorly
after planting is because the plants are watered too often, and the crown or
roots drown. Asparagus must be planted in soils that don’t hold water. If the
soil holds water easily or there is poor drainage then consider planting
asparagus crowns just below the surface of the soil and mound the soil eight or
10 inches above it. Mounding the soil provides better drainage in heavier soil.
Don’t
water deep rooted asparagus the same as other annual vegetables. They could be
watered with other perennial vegetables such as artichokes or even fruit trees
or landscape trees and shrubs! If in doubt, use a soil moisture meter with the
tip inserted at about 4 to 6 inches deep in the soil. Never trust a dry soil
surface to tell you if the soil where the roots are growing is dry or wet. Water
again when the average needle measurements register midway or around “5” on the
moisture gauge.
Asparagus
grows in the wild near the edges of irrigation ditches in the desert. But not in the
ditch. This means they like to get their “toes” occasionally wet but not
submerged. These locations are similar where palm and fig trees like to grow. I
had good luck growing asparagus between fruit trees when they were young and there
is enough light. When fruit trees get older and dense, it is more difficult to
grow asparagus because there is less light. Move the crowns to new locations
during the winter months where there is moisture and adequate light.
Adding
rock beneath the crowns doesn’t help drainage at all. It’s the same story with
sand. To get any kind of soil improvement requires additions of 80 to 90% sand
above and below where the plant roots are growing. Research has not looked at
gravel but I assume it is the same. But additions of rock above the crowns
cause them grow crooked spears. Straight spears require soil above the crowns
without rocks.
In my
trials over the years, all varieties of asparagus (12 different varieties) produced
spears but the longest and most saleable spears were produced by UC151 hybrids
bred by the University of California in Riverside for the hot, dry desert. All
the “Jersey” varieties, bred by Rutgers University (New Jersey), didn’t yield as
well in the Mojave Desert. You get quality spears with other varieties, but the
spears must be harvested earlier than UC151 and this makes them shorter. This
holds true for old-fashioned varieties like Martha Washington and most purple
types.
I
fertilize asparagus in midwinter with a layer of manure or compost applied once
a year and watered in. You can also use a high nitrogen fertilizer, but it will
not improve the soil like manure or compost does.